CO129-562-12 Dysentry epidemic- recommendation to enforce compulsory pasteurization of milk 7-6-1937 - 17-8-1937 — Page 42

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will be prohibited at any rate in some districts at a not too distant date.

170. In coming to the conclusion that a reasonable period should be allowed to elapse before pasteurisation was anywhere made compulsory we have indeed been influenced by a desire to prevent an injury to an important section of the farming community. But considerations of public health alone would have led us to the same conclusion. For many reasons it is impossible to pasteurise milk except in large urban areas. In country districts and in the smaller towns, failing a milk supply which is healthy at the source, the consumer can safeguard himself only by boiling all milk-for infected milk may be made safe for human consumption by heating it in a double saucepan until the water in the outer pan comes to the boiling point.* Though we strongly urge the adoption of this practice, we cannot hope that medical education would bear such fruit in the districts we are considering that in every household all milk from tuberculous herds would be carefully treated in the manner prescribed above. Thus, only the eradication of the disease among cows themselves will secure the rural population against the dangers of infection with bovine tuberculosis. A policy of pasteurisation which was so carried into execution that it promoted the eradication of tuberculosis from cattle in districts surrounding large urban areas would inevitably have the effect of creating a demand for cattle from tuberculosis-free herds for replacement purposes in these districts. The expectation of this demand would promote the eradication of tuberculosis in the rural areas from which supplies of cattle for replace- ment purposes were drawn, and the human population of these areas would benefit immediately. Moreover, the immediate advantage to public health of introducing compulsory pasteurisation, without regard to its repercussions on the prospects of eradication, must not be exaggerated. It must be remembered that, under our scheme, all

* Two experiments with tuberculous milk are quoted to show the efficaciousness of this simple method of heat-treatment of milk in the home:

Experiment 1.-Some heavily-infected milk was brought to the boiling- point of water in a double saucepan; the gas was then turned out and the milk was left for 15 minutes, after which it was rapidly cooled. A dose of 0.5 c.c. of the unboiled milk caused general tuberculosis in 2 guinea-pigs; the heat-treated milk was inoculated into 2 guinea-pigs, each receiving 5.0 c.c., that is 10 times the amount used for the controls. They remained free from tuberculosis.

Experiment 2.-A sample of milk heavily infected with tubercle bacilli was again used. In this experiment the test was more severe, as the treatment was purposely less thorough. The inner pan did not touch the water in the outer pan and, as soon as steam began to issue, the inner pan, containing the milk, was removed and immersed in cold water. The maximum temperature reached by the milk was 85.0 C. (185·0° F.). The unheated milk, in a dose of 0.01 c.c., produced general tuberculosis in 2 guinea-pigs. The heated milk, dose 5-0 c.c., that is 500 times as much as was used for the controls, did not produce tuberculosis in 2 guinea-pigs.

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